import java.util.Objects;

public class Test06 {
    public static void main(String[] args) throws CloneNotSupportedException {
        int[] data={1,2,3,4,5,6,7,8,9};
        User u1=new User(1,"张三","123","may",data);
        User u2=new User();
        u2=(User)u1.clone();
        int[] arr=u1.getData();
        arr[0]=100;
        System.out.println(u1);
        System.out.println(u2);
        Student s1=null;
        Student s2=new Student("张三",23);
        System.out.println(Objects.equals(s1,s2));
        System.out.println(Objects.isNull(s1));
        System.out.println(Objects.nonNull(s2));

    }
}
